Thursday, September 25, 2014

docker presentation

You can find the Docker presentation I did for Sony eurasia below.

Tuesday, July 1, 2014

access to dialectResolutionInfo cannot be null when 'hibernate.dialect' not set

While I was trying JPA stuff on Spring Boot I had a "Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set" exception. I was using "spring-boot-starter-data-jpa" and everything seemed to be in place but still I was getting this. Later I realized that I did not include my database's dependency. After I added it to my pom the problem was fixed.



  postgresql
  postgresql
  9.1-901.jdbc4

Thursday, June 26, 2014

spring boot presentation

Yesterday I did a Spring Boot presentation at Sony Eurasia. Here are the slides:


Wednesday, June 4, 2014

spring social example on spring boot or how I stopped worrying and loved autoconfiguration

As of Spring Boot 1.1.0.RC1, autoconfiguration and the starter pom of Spring Social  is added which means that I won't have to add a hundred dependency to my pom and lots of meaningless Spring configuration will be handled for me. Let's see how it works on an example.

 I will implement a web application of two pages. One will show the given user's Twitter timeline and the other user's profile information. Here's my pom:



    4.0.0

    nr.co.caught
    BootTwitterJoy
    1.0-SNAPSHOT
    war

    
    
        org.springframework.boot
        spring-boot-starter-parent
        1.1.0.RC1
    

    
        
            org.springframework.boot
            spring-boot-starter-social-twitter
        

        
        
            org.apache.tomcat.embed
            tomcat-embed-jasper
        
        
            javax.servlet
            jstl
        

    

    
    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

    
    
    
        
            spring-snapshots
            http://repo.spring.io/snapshot
            
                true
            
        
        
            spring-milestones
            http://repo.spring.io/milestone
        
    
    
        
            spring-snapshots
            http://repo.spring.io/snapshot
        
        
            spring-milestones
            http://repo.spring.io/milestone
        
    


As you can see, I have my starter-social-twitter dependency which gives me Spring Social and Web capabilities. I'll add jasper and jstl for my jsp pages to work. My repositories part is quite populated due to the milestone repositories.
Now we will add our Service to do Twitter method calls and a Controller for handling the requests. Our Controller is plain and simple:
@Controller
public class TwitterController {

    @Autowired
    private TwitterService twitterService;

 @RequestMapping(value = "/timeline/{twitterUser}")
 public String getUserTimeline(@PathVariable String twitterUser, Model model) {
        model.addAttribute("tweets", twitterService.getUserTimeline(twitterUser));
        model.addAttribute("user", twitterUser);

  return "timeline";
 }

    @RequestMapping(value = "/profile/{twitterUser}")
    public String getUserProfile(@PathVariable String twitterUser, Model model) {
        model.addAttribute("userProfile", twitterService.getUserProfile(twitterUser));

        return "profile";
    }
}
If the request comes with "/timeline/username", our controller will get the user timeline and if it comes with "/profile/username" it will get the user profile from TwitterService. Here's our TwitterService:
@Service
public class TwitterService {

   @Autowired
    private Twitter twitter;

    public List < Tweet > getUserTimeline(String twitterUser) {
        TimelineOperations timelineOps = twitter.timelineOperations();
        List tweets = timelineOps.getUserTimeline("@" + twitterUser);

        return tweets;
    }

    public TwitterProfile getUserProfile(String twitterUser) {
        UserOperations userOperations = twitter.userOperations();
        TwitterProfile userProfile = userOperations.getUserProfile(twitterUser);

        return userProfile;
    }
}
We have a Twitter object that'll be created thanks to Spring Boot's autoconfiguration. We just have to provide an app id and app secret key (a.k.a. consumer key and consumer secret) in our application properties and Boot will do the rest. I'm quoting Twitter object explanation from Spring javadoc: "This instance of TwitterTemplate is limited to only performing operations requiring client authorization. For instance, you can use it to search Twitter, but you cannot use it to post a status update. The client credentials given here are used to obtain a client access token via OAuth 2 Client Credentials Grant". If you try to do a status update, you'll get "org.springframework.social.MissingAuthorizationException: Authorization is required for the operation, but the API binding was created without authorization". For further Twitter functionality, we would need to provide access token and access token secret keys as well but as far as I know autoconfiguration would not handle these cases yet.
My JSPs:
profile.jsp:
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title></title>
</head>
<body>
<img src="${userProfile.profileImageUrl}"/>  
Screen name: ${userProfile.screenName}
Name: ${userProfile.name}
Description: ${userProfile.description}
Location: ${userProfile.location}
Followers: ${userProfile.followersCount}
</body> </html>
As you can see, profile takes the userProfile provided by our Controller and show the basic profile properties. timeline.jsp
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Time Line for <c:out value="${twitterUser}" /> TimeLine</title>
</head>
<body>
<ul>
    <c:forEach items="${tweets}" var="tweet">
        <li>${tweet.text}
at <c:out value="${tweet.createdAt}"/></li> <br/> </c:forEach> </ul> </body> </html>
Tweets are shown with their text and creation date. My application.properties content:
# Config for JSPs
spring.view.prefix: /WEB-INF/jsp/
spring.view.suffix: .jsp

# SPRING SOCIAL TWITTER (TwitterAutoConfiguration)
spring.social.twitter.appId= someAppId
spring.social.twitter.appSecret= someSecretId
spring.view properties are for the jsp handling. spring.social.twitter properties can be obtained from http://dev.twitter.com. Just login there with your twitter account, create your app and get your api keys. Here's the result:




You can check the code at github.

Thursday, May 29, 2014

exception after main class package change in spring boot

In my Spring Boot toy project ( web + mongodb), I want to change the structure of my packages. My old structure was like this:

Putting @ComponentScan annotation (without a base package) was fine for scanning all my classes. But when I update the structure and moved my main file (BootQeyfi) to launch package, I needed to update base package with
@ComponentScan(basePackages = "main") . After that definition Spring will scan the main as a base package and handle everything perfectly.

But of course that's not the case. I got the following exception which basically means "I could not autowire your repository class (your interface which extends MongoRepository)" 
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'helloController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private main.service.HelloService main.controller.HelloController.service; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'helloService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: main.dao.ProductRepository main.service.HelloService.repository; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [main.dao.ProductRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
 at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:292)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
 at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
 at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
 at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:703)
 at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760)
 at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
 at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:120)
 at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:648)
 at org.springframework.boot.SpringApplication.run(SpringApplication.java:311)
 at launch.BootQeyfi.main(BootQeyfi.java:27)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private main.service.HelloService main.controller.HelloController.service; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'helloService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: main.dao.ProductRepository main.service.HelloService.repository; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [main.dao.ProductRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
 at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:508)
 at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
 at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
 ... 14 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'helloService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: main.dao.ProductRepository main.service.HelloService.repository; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [main.dao.ProductRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
 at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:292)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
 at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
 at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
 at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1017)
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:960)
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:858)
 at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)
 ... 16 more
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: main.dao.ProductRepository main.service.HelloService.repository; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [main.dao.ProductRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
 at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:508)
 at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
 at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
 ... 27 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [main.dao.ProductRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1103)
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:963)
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:858)
 at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)
 ... 29 more
To fix this problem, @EnableMongoRepositories must be added to your main class. My repository is under "main.dao" so my definition is like @EnableMongoRepositories(basePackages = "main.dao").